Outdoor testing grounds are conventionally used to evaluate a tire's performance under various snow and ice conditions. Standardized methodology for evaluating tire traction and other performance data is widely practiced within the industry. One such ASTM standard followed by the industry includes ASTM designation: F 1805-98 entitled, “Standard Test Method for Single-Wheeled Driving Traction in a Straight Line on Snow—and Ice—Covered Surfaces” and which is incorporated herein by reference. The ASTM methodology sets forth a procedure used by the tire industry to evaluate a tire's performance on snow and ice.
There currently exists outdoor tire evaluation test tracks. These test tracks are utilized for tire evaluation techniques on snow and ice using the ASTM procedures described above. The performance characteristics of a given tire are made in comparison to the performance of a reference tire. The standard specification for a radial reference test tire uses the ASTM standard E 1136-93 (Re-approved in 1998) and which is incorporated herein by reference.
In the development of a new tire, it is desirable to undergo snow performance evaluation of the tire. Further, a snow evaluation setting forth minimum performance standards is required before a tire may carry industry designations as a snow tire.
Outdoor test facilities make every effort to maintain a uniform and reproducible snow track surface. However, there are inherent limitations in an outdoor track's ability to maintain a uniform evaluation snow track. Fluctuations in temperature, natural snowfall, humidity, and the presence or absence of direct sunlight are all factors that can produce differences in the quality and characteristics of the snow test surface. Indeed, changes over a single day can bring about significant differences in the quality of the test track surface. Further, there are additional limitations to outdoor evaluation tracks since such tracks operate on a seasonal basis and are largely dependent upon natural snowfall.
There have been prior efforts within the art to carry out tire evaluations on indoor manufactured snow surfaces. These efforts have included blowing layers of snow followed by packing of the blown snow. In addition, applications of water to the snow surface have been used in an attempt to improve the snow quality. While such an artificial snow surface may permit relative traction or braking comparisons between tires, there remains room for improvement in the art.